It is known to impregnate at super-atmospheric pressure a still (i.e. substantially gas-free) liquid with a gas from an external source. This type of impregnation is usually employed in the prior art to make the liquid effervescent. As described in US. Pat. No. 2,927,028, "such artificial impregnation of a liquid with a gas has hitherto been carried out by bubbling the gas through the liquid, or by spraying the liquid into the gas, or by otherwise violently agitating the liquid in the presence of the gas, so as to increase as much as possible the area of surface contact between the liquid and the gas and hasten the entry of the gas into the liquid, the treatment being continued until the pressure of the gas in the liquid is substantially equalled to the applied pressure. The impregnation of the liquid with gas is usually carried out in large vessels and the impregnated liquid is subsequentially transferred to the bottles or other containers in which it is to be marketed, a counter pressure of gas being maintained in these vessels while they are being filled, in order to prevent so far as possible the escape of gas from the liquid." Such a method has not been found to be successful to produce oxygen enriched liquids to achieve either a high level of dissolved oxygen, or to retain the dissolved oxygen in the liquid for an appreciable length of time.
Our U.S. Pat. No. 5,006,352 did provide a process for overcoming some of these drawbacks of the prior art as it applies to the incorporation of oxygen in water. That patent describes a process for enriching water with oxygen, wherein the liquid is saturated with oxygen at a temperature between 0.degree. C. and 5.degree. C. under pressure, and then bottling and sealing the bottle containing the enriched water. The presence of oxygen does not affect the taste of the water and its consumption has a favorable effect on well being and physical performance. A drawback of this process is that it requires the use of low temperatures, achieves a still relative low level of dissolution of oxygen in the water, and results in a relatively fast loss of the oxygen enrichment when the enriched water is exposed to ambient pressure.
U.S. Pat. No. 4,027,045 discloses another process for preparing an oxygenated cocktail. None of the oxygenation processes have proved successful for a producing sufficiently high oxygen loading of the liquid. Suggestions were made in the prior art for increasing oxygen available for various aerobic and therapeutic processes by the use of oxygen enriched water and other liquids. However, the lack of ways to obtain a sufficiently high degree of oxygen enrichment of water did not enable any effective follow-up on such suggestions.